Risk Factors for Emergency Room and Hospital Care Among Patients With Solid Tumors on Immune Checkpoint Inhibitor Therapy

Objectives: Immune checkpoint inhibitors (ICIs) are being increasingly used across cancer types. Emergency room (ER) and inpatient (IP) care, common in patients with cancer, remain poorly defined in this specific population, and risk factors for such care are unknown. Methods: We retrospectively reviewed charts for patients with solid tumors who received >1 ICI dose at 1 of 2 sites from January 1, 2011 to April 28, 2017. Demographics, medical history, cancer diagnosis/therapy/toxicity details, and outcomes were recorded. Descriptive data detailing ER/IP care at the 2 associated hospitals during ICI therapy (from first dose to 3 mo after last dose) were collected. The Fisher exact test and multivariate regression analysis was used to study differences between patients with versus without ER/IP care during ICI treatment. Results: Among 345 patients studied, 50% had at least 1 ER visit during ICI treatment and 43% had at least 1 IP admission. Six percent of ER/IP visits eventually required intensive care. A total of 12% of ER/IP visits were associated with suspected or confirmed immune-related adverse events. Predictors of ER care were African-American race (odds ratio [OR]: 3.83, P=0.001), Hispanic ethnicity (OR: 3.12, P=0.007), and coronary artery disease (OR: 2.43, P=0.006). Predictors of IP care were African-American race (OR: 2.38, P=0.024), Hispanic ethnicity (OR: 2.29, P=0.045), chronic kidney disease (OR: 3.89, P=0.006), angiotensin converting enzyme inhibitor/angiotensin receptor blocker medication use (OR: 0.44, P=0.009), and liver metastasis (OR: 2.32, P=0.003). Conclusions: Understanding demographic and clinical risk factors for ER/IP care among patients on ICIs can help highlight disparities, prospectively identify high-risk patients, and inform preventive programs aimed at reducing such care.